Numerical simulation of vortical and coherent structures in compressible jet flows

The compressible flows of plane free jets and jets of the intake-stroke of a rectangular piston-engine model are investigated by numerical simulations. The observed vortical structures appear to be the well-known coherent structures of turbulent shear layers. The simulated structures are compared to experimental data by means of density fields and turbulent statistics taken from different authors. The computed flow depends on physical as well as on numerical parameters. The good agreement with the experimental data is obtained by direct simulation without any turbulence model.